Li Lanjuan's new paper: COVID-19 is evolving! Mutations affecting pathogenicity have occurred, and live viruses have been isolated from feces

• by EVOMT
• 2020-04-22

On April 19, Li Lanjuan, an academician of the CAE Member, published the latest achievements on the preprint platform medRxiv. Researchers conducted ultra deep sequencing of 11 virus isolates from patient sources and found a total of 33 mutations, of which 19 were the first new mutations discovered. COVID-19 has appeared mutations that can effectively affect the pathogenicity. The virus load within 24 hours differs by nearly 270 times between those with the strongest and weakest replication capabilities.

The researchers believe that despite analyzing only viruses isolated from 11 patients, a rich diversity of mutations has been observed. This shows that the true diversity of COVID-19 strains is still greatly underestimated.

The researchers used a Vero-E6 cell line with ACE2 receptors that are very similar to human cells. They infected Vero-E6 cells with viruses from all 11 patient sources, and collected cells at regular intervals to detect the viral load of the cells.

The results showed that during the first four hours, the viral load remained stable and replication rarely occurred. After 8 hours, the viral load from patients 6, 7, 9, 10, and 11 significantly increased. After 24 hours, the viral load of all viruses except No. 2 and No. 7 increased significantly, while the increase speed of No. 10 and No. 11 was much faster than that of others.

Further testing at 48 and 72 hours revealed that the higher the viral load, the higher the pathological effect and mortality of the cells. A trinucleotide mutation occurred in the virus from patient 11, which greatly increased the replication rate and pathogenicity of the virus strain. This patient's virus test was positive and maintained for 45 days.

In addition, three virus isolates in this study came from stool samples of patients, which indicates that COVID-19 does have the ability to replicate in stool.

Finally, the researchers called for the research and development of COVID-19 drugs and vaccines to take into account the impact of these cumulative mutations as soon as possible.

Fortunately, as of the time of writing of this paper, all 11 patients described in the article have recovered and discharged.